using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Newtonsoft.Json;

using SearchBox;


namespace SearchBoxCLI
{
	enum OperatingModes
	{
		Query,
		Index,
		InvertedIndexAdd,
		InvertedIndexRemove,
		InvertedIndexUpdate
	}

	enum OutputModes
	{
		Json,
		Text
	}

	class MainClass {
		private static OperatingModes Mode = OperatingModes.Query;
		private static string Name = string.Empty;
		private static string InvIndexFilepath = string.Empty;
		private static string IdMapFilepath = string.Empty;
		private static TextReader Source = Console.In;
		private static OutputModes OutputMode = OutputModes.Json;

		public static int Main(string[] args)
		{
			List<string> extras = new List<string>();
			for (int i = 0; i < args.Length; i++)
			{
				switch (args[i].TrimStart("-".ToCharArray()))
				{
					case "s":
					case "source":
						Source = new StreamReader(args[++i]);
						break;

					case "n":
					case "name":
						Name = args[++i];
						break;

					case "invindex":
						InvIndexFilepath = args[++i];
						break;

					case "idmap":

						break;

					case "help":
						Console.WriteLine("SearchBox");
						Console.WriteLine("---------");
						Console.WriteLine("A standalone full-text search engine.");
						Console.WriteLine();
						Console.WriteLine("Usage:");
						Console.WriteLine("    ./SearchBox.exe {mode} [options]");
						Console.WriteLine();
						Console.WriteLine("Modes:");
						Console.WriteLine("    query     Query a pre-existing inverted search index");
						Console.WriteLine("    index     Generate a raw index of the source document.");
						Console.WriteLine("    add       Add a named document to an inverted search index.");
						Console.WriteLine("    remove    Remove a named document from an inverted search index.");
						Console.WriteLine();
						Console.WriteLine("Options:");
						Console.WriteLine("    --source, -s    Specifies the source document {index, add}");
						Console.WriteLine("    --name, -n      Sets the name of the source document {add, remove}");
						Console.WriteLine("    --idmap, -i     Specifies the location of the id map, which is used to map document names onto their nuemical ids {add, remove}");
						Console.WriteLine("    --invindex      Specifies the location of the inverted search index to use {add, remove}");
						Console.WriteLine("    ");
						break;

					default:
						Console.Error.WriteLine($"Error: Unknown property {args[i]}.");
						return 1;
				}
			}

			string modeText = extras.First(); extras.RemoveAt(0);
			Mode = (OperatingModes)Enum.Parse(typeof(OperatingModes), modeText);

			switch (Mode) {
				case OperatingModes.Index: return HandleIndex();
				case OperatingModes.InvertedIndexAdd: return HandleInvIndexAdd();
			}

			return 0;
		}

		private static int HandleInvIndexAdd()
		{
			if (!File.Exists(InvIndexFilepath))
				File.WriteAllText(InvIndexFilepath, "[]");
			if (!File.Exists(IdMapFilepath))
				File.WriteAllText(InvIndexFilepath, "{}");

			IdMap idMap = JsonConvert.DeserializeObject<IdMap>(File.ReadAllText(IdMapFilepath));
			InvertedIndex invertedIndex = JsonConvert.DeserializeObject<InvertedIndex>(
				File.ReadAllText(InvIndexFilepath)
			);
			Index newIndex = new Index(Source.ReadToEnd());
			invertedIndex.AddIndex(newIndex);

			return 0;
		}

		public static int HandleIndex()
		{
			Index index = new Index(Source.ReadToEnd());
			switch (OutputMode)
			{
				case OutputModes.Json:
					Console.WriteLine(JsonConvert.SerializeObject(index));
					break;
				case OutputModes.Text:
					Console.WriteLine(index);
					break;
			}

			return 0;
		}
	}
}